/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package decode;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.KeyGenerator;
import java.security.spec.KeySpec;
import java.security.spec.AlgorithmParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEParameterSpec;
import java.security.InvalidAlgorithmParameterException;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidKeyException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import java.io.UnsupportedEncodingException;
import java.io.IOException;
import sun.misc.BASE64Encoder;
import sun.misc.BASE64Decoder;

/**
 * Clase encargada de Encriptar y Desencriptar Valores
 * @author Administrador
 */
public class crypto {
    /**
     * Encargada de encriptacion y desencriptacion
     */
    public crypto(){        
    }
    Cipher ecipher;
    Cipher dcipher;
    /**
     * Inicializar el metodo de cifrado
     * @param key
     * Clave principal
     * @param algorithm
     * Algoritmo para realizar el cifrado
     */
    public void StringEncrypter(SecretKey key, String algorithm) {
        try {
            ecipher = Cipher.getInstance(algorithm);
            dcipher = Cipher.getInstance(algorithm);
            ecipher.init(Cipher.ENCRYPT_MODE, key);
            dcipher.init(Cipher.DECRYPT_MODE, key);
        } catch (NoSuchPaddingException e) {
            System.out.println("EXCEPTION: NoSuchPaddingException");
        } catch (NoSuchAlgorithmException e) {
            System.out.println("EXCEPTION: NoSuchAlgorithmException");
        } catch (InvalidKeyException e) {
            System.out.println("EXCEPTION: InvalidKeyException");
        }
    }
    /**
     * Encargada de crear la llave
     * @param passPhrase
     * Clave principal
     */
   public void StringEncrypter(String passPhrase) {
        // 8-bytes Salt
        byte[] salt = {
            (byte) 0xA9, (byte) 0x9B, (byte) 0xC8, (byte) 0x32,
            (byte) 0x56, (byte) 0x34, (byte) 0xE3, (byte) 0x03
        };
        // Iteration count
        int iterationCount = 19;
        try {
            KeySpec keySpec = new PBEKeySpec(passPhrase.toCharArray(), salt, iterationCount);
            SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
            ecipher = Cipher.getInstance(key.getAlgorithm());
            dcipher = Cipher.getInstance(key.getAlgorithm());
            // Prepare the parameters to the cipthers
            AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
            ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
            dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
        } catch (InvalidAlgorithmParameterException e) {
            System.out.println("EXCEPTION: InvalidAlgorithmParameterException");
        } catch (InvalidKeySpecException e) {
            System.out.println("EXCEPTION: InvalidKeySpecException");
        } catch (NoSuchPaddingException e) {
            System.out.println("EXCEPTION: NoSuchPaddingException");
        } catch (NoSuchAlgorithmException e) {
            System.out.println("EXCEPTION: NoSuchAlgorithmException");
        } catch (InvalidKeyException e) {
            System.out.println("EXCEPTION: InvalidKeyException");
        }
    }
    /**
     * Encriptar una cadena
     * @param str
     * Cadena a encriptar
     * @return
     * Cadena encriptada
     */
    public String encrypt(String str) {
        try {
            // Encode the string into bytes using utf-8
            byte[] utf8 = str.getBytes("UTF8");
            // Encrypt
            byte[] enc = ecipher.doFinal(utf8);
            // Encode bytes to base64 to get a string
            return new sun.misc.BASE64Encoder().encode(enc);
        } catch (BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (IOException e) {
        }
        
        return null;
    }

    /**
     * Desencriptar una cadena
     * @param str
     * Cadena a desencriptar
     * @return
     * Cadena desencriptada
     */
    public String decrypt(String str) {
        try {
            // Decode base64 to get bytes
            byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
            // Decrypt
            byte[] utf8 = dcipher.doFinal(dec);
            // Decode using utf-8
            return new String(utf8, "UTF8");

        } catch (BadPaddingException e) {
        } catch (IllegalBlockSizeException e) {
        } catch (UnsupportedEncodingException e) {
        } catch (IOException e) {
        }
        return null;
    }

}
